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Amedee
Amedee, Jeep Technician
Category: Jeep
Satisfied Customers: 25400
Experience:  ASE certified Technician advanced level specialist. Wisconsin certified emissions state inspector
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I've got the problem that is apparently a classic with Jeep

Customer Question

I've got the problem that is apparently a classic with Jeep Grand Cherokee cars. In my newly-acquired 2000 Jeep Grand Cherokee, sometimes the engine will just die at a light or will not start. It cranks but will not fire. The gauges appear dead, too.
Two fixes I have now heard about - (1) wiggle the multi-pin harness cable connector near the firewall & windshield spray tank. Has not fixed problem and I had to get a tow. (2) tighten the star screws and ground tabs on the PCM main computer (not tried yet). Ideas ??
Submitted: 6 months ago.
Category: Jeep
Expert:  Amedee replied 6 months ago.

Hello and welcome!

My name isCustomerand I can assist you with your question.

Expert:  Amedee replied 6 months ago.

I see this problem all of the time and I know exactly what is going on and how to fix. It would be better to explain over the phone. Would you be willing to speak on the phone?

Customer: replied 6 months ago.
I'm now in a mtg, please see my statement of the problem earlier and let me know your advice to take the next step, thanks. I do think talking on the phone will also be good when we are both free.
Expert:  Amedee replied 6 months ago.

Hello!

I have seen the statement above.

What is MTG?

Customer: replied 6 months ago.
It's great that you have a lot of experience with solving this problem. I was thinking that talking with you would be easier than emailing. Then the site popped-up with a new charge for talking. So let's start with a written description of your advice for solving this problem. Thank you !
Expert:  Amedee replied 6 months ago.

Hello and good morning!

Sounds good no problem. I will be happy to help anyway I can.

A few questions.

What size engine do you have?

Can I get your VIN by chance?

Have you checked for any codes in the computer?

Customer: replied 6 months ago.
Good show !
Here is the VIN 1J4G248N4YC278209
There have been NO codes in the computer.
Expert:  Amedee replied 6 months ago.

Thank you very much for the VIN!

The problem you are experiencing is a BUS communication failure. This will affect both areas you are describing (stalling, no start and gauges inop). The BUS circuit is a communication network circuit that all of the modules on board the vehicle communicate on or with one another. If this circuit gets shorted out some how (by a bad module or a wiring issue), the gauges will stop responding and vehicle may stall and not start back up again.

Based on your VIN, the most likley modules on board the vehicle to go bad causing these conditions are the following..

PCM

BCM

Instrument cluster

Expert:  Amedee replied 6 months ago.

Hello!

I see you have viewed my last reply but have not responded back. I am just checking in to see if you have any further questions or to see if you still need help with anything? If so, please let me know as I will be happy to help. If I have answered all of your questions, please dont forget to honor the good faith rating system to complete this conversation.

Customer/p>
Customer: replied 6 months ago.
The PCM was just replaced a few months ago by the guy who sold me the car, he was working to solve this same problem, so that is not the problem. How do I test if the BCM or the instrument cluster are the problem ?
Expert:  Amedee replied 6 months ago.

You could simply disconnect them to see if there is any improvement.

Customer: replied 6 months ago.
But will the car even start if they are disconnected ? And how / where to disconnect ?
Expert:  Amedee replied 6 months ago.

If there is a no communication problem with the computer, you dont have to try and start the vehicle, you could simply disconnect one of these modules and the communication should resume once the key is turned to the ON position. The BCM is located under the hood, on the drivers side attached to the firewall. The cluster of course is the gauges right in front of the driver above the steering wheel.

Customer: replied 6 months ago.
OK, I'm out of town today and tomorrow...I'll check this out later in the week. Again, if I understand you, it is OK to just disconnect a plug connector to the BCM or to the instrument cluster and see if the remaining modules start to talk. Right ?
Expert:  Amedee replied 6 months ago.

You got it!!!

Customer: replied 6 months ago.
Roger. I'll get back to you ASAP.
Expert:  Amedee replied 6 months ago.

Sounds good!

Expert:  Amedee replied 5 months ago.

Hello!

It'sCustomerand I just wanted to check in to see how things are going and to see if you need any further assistance?

Customer: replied 5 months ago.
ThanksCustomer --
I'll let you know after I get some feedback from checking out the BUS communication as we discussed.
Expert:  Amedee replied 5 months ago.

Sounds good! Thanks for the update!